1. Field of the Invention
The present invention relates to pulse combustion devices using flapper-type gas and air inlet valves, and more particularly to an improvement of an air intake system in the pulse combustion device.
2. Description of the Prior Art
In a conventional pulse combustion device of this kind, flapper-type gas and air inlet valves are adapted to supply gaseous fuel and air at an optimum mixing ratio into a combustion chamber, and a tailpipe is connected to the combustion chamber to bring about therein pulse combustion of the mixture of gaseous fuel and air and to exhaust therefrom the combustion products. In FIG. 3 there is illustrated such a conventional pulse combustion device as described above which comprises a housing 8' forming therein a combustion chamber 10' and being provided thereon with a spark plug 13', a cylindrical support member 5' coupled in a fluid-tight manner with an open end of housing 8' through a perforated flame trap 11' and forming therein a mixing chamber 4', a partition member 1a' secured to a flanged open end of support member 5' and defining a side wall of an air chamber 1', a cylindrical gas distribution head 3' mounted in the center of partition member 1a' and having an inner end portion formed with a plurality of circumferentially spaced radial holes 3a' for communication with the mixing chamber 4', a gas container 2' arranged within the air chamber 1' to store therein an amount of gaseous fuel under pressure and having a cylindrical projection 2a' coupled within the distribution head 3' in a fluid-tight manner, a plurality of circumferentially equally spaced flapper-type air inlet valve units V.sub.1 ' mounted on the partition member 1a' to allow inward flow of air passing therethrough into the mixing chamber 4' from the air chamber 1' and to block outward flow of the air from the mixing chamber 4', a flapper-type gas inlet valve unit V.sub.3 ' mounted on an end wall of the cylindrical projection 2a' of container 2' and arranged within the distribution head 3' to allow inward flow of gaseous fuel passing therethrough into the mixing chamber 4' from the gas container 1' and to block outward flow of the gaseous fuel from the mixing chamber 4'.
In operation of the conventional pulse combustion device, gaseous fuel under pressure is supplied into the mixing chamber 4' from the gas container 2' through the gas inlet valve unit V.sub.3 ' and distribution head 3', while air is supplied into the mixing chamber 4' from the air chamber 1' through the air inlet valve units V.sub.1 '. The gaseous fuel is mixed with the incoming air at an optimum mixing ratio in the mixing chamber 4' and supplied into the combustion chamber 10' through the flame trap 11'. When the mixture of gaseous fuel and air is iginited by energization of the spark plug 13', the pressure of the resulting rapid combustion of the mixture closes the air and gas inlet valve units V.sub.1 ', V.sub.3 ' and forces the combustion products to exhaust from the tailpipe. During combustion of the mixture in the combustion chamber 10', the mixture is explosively burnt in a moment when introduced into the combustion chamber 10'. This results in an increase of combustion noise in the combustion chamber 10'. Moreover, it is difficult to increase or decrease heating capacity of the pulse combustion device by adjustment of the supply amount of gaseous fuel into the mixing chamber 4'. Namely, the adjustment range of heating capacity is very narrow. For these reasons, the application of the pulse combustion device is limited only to a gas equipment such as a gas fryer which requires no change of its heating capacity during operation.